High melting polymers of sulfur dioxide with olefins, such as ethylene, have been known for many years. Such polymers are generally prepared by reacting the monomers in the presence of a free radical catalyst, such as a peroxide, and the polymers typically consist of alternating units of sulfur dioxide and olefin having a 1:1 molar ratio in the polymer chain. Copolymers of sulfur dioxide and ethylene having a ratio greater than one have also been prepared, for example, as disclosed in U.S. Pat. Nos. 2,943,077 and 3,657,202.
Terpolymers of sulfur dioxide, olefins and carbon monoxide are also well known. For example, U.S. Pat. No. 2,634,254 discloses such terpolymers prepared by polymerizing sulfur dioxide, ethylene and carbon monoxide in the presence of free radical generating catalysts such as azo compounds. U.S. Pat. No. 4,251,340 discloses similar terpolymers prepared by irradiation of a mixture of sulfur dioxide, carbon monoxide and ethylene. These terpolymers are generally high melting polymers stable up to a temperature of about 280.degree. C. The polymers show good durability and structural properties and the polymers have particular utility in high temperature applications.
It would be desireable to have a new process to prepare polymers of sulfur dioxide, olefins and optionally carbon monoxide.